Does light have an infinite lifetime?
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Does light have an infinite lifetime?
1–10 of 106 posts
Re: Does light have an infinite lifetime?
#2Interesting. I had no idea that the universe would eventually be basically just photons. I wonder if that is why Stephen Baxter had his 'photino birds' as the final form of life in his Xeeleverse?
Re: Does light have an infinite lifetime?
#3Huh? Light has zero lifetime, along with all massless particles. When you travel at c your clock doesn’t tick. From the viewpoint of a photon it is emitted and absorbed at the same instant. You cannot decay if you don’t experience time. I’m not sure exactly how index of refraction works with this.
Re: Does light have an infinite lifetime?
#4Huh? Light has zero lifetime, along with all massless particles. When you travel at c your clock doesn’t tick. From the viewpoint of a photon it is emitted and absorbed at the same instant. You cannot decay if you don’t experience time. I’m not sure exactly how index of refraction works with this.
> You cannot decay if you don’t experience time.
Interesting take! But if photons couldn't decay due to not experiencing time, they couldn't do anything else either.
The reality is that a photons creation and destruction are not prohibited, but simply "experienced" as two events at different locations at the same time, with the photon being the "thing" that connects those events.
Given that interpretation, it might be reasonable to assume that all photons have beginnings and ends, regardless of the duration we perceive between them, or they wouldn't exist.
Time being no barrier at all for photons.
Re: Does light have an infinite lifetime?
#5I feel like this article could be condensed into a simple answer. I got tto annoyed looking for it to find more than the answer, "yes, if the standard model holds"
So at the risk of venting unconstructively, I wish I had a way of screening physics writing that is not a physics paper. Articles like this are frustrating because they only have one or two interesting tidbits for me, but they hide them in a whole lot of highschool level hand waving.
Honestly HN would be perfect if it only allowed physics papers - no pop-physics - and if it banned any blogs or news sites with paywalls or newsletter nagware (looking at you, medium, new york times).
Alas. I'm wishing for something I will have to build if I really want it.
Re: Does light have an infinite lifetime?
#6Huh? Light has zero lifetime, along with all massless particles. When you travel at c your clock doesn’t tick. From the viewpoint of a photon it is emitted and absorbed at the same instant. You cannot decay if you don’t experience time. I’m not sure exactly how index of refraction works with this.
> You cannot decay if you don’t experience time. Interesting take! But if photons couldn't decay due to not experiencing time, they couldn't do anything else either. The reality is that a photons creation and destruction are not prohibited, but simply "experienced" as two events at different locations at the same time, with the photon being the "thing" that connects those events. Given that interpretation, it might b…
Would that seem like a fold in spacetime to the photon?
Re: Does light have an infinite lifetime?
#7[flagged]
Re: Does light have an infinite lifetime?
#8Earlier quoted context omitted.
> You cannot decay if you don’t experience time. Interesting take! But if photons couldn't decay due to not experiencing time, they couldn't do anything else either. The reality is that a photons creation and destruction are not prohibited, but simply "experienced" as two events at different locations at the same time, with the photon being the "thing" that connects those events. Given that interpretation, it might b…
Would that seem like a fold in spacetime to the photon?
Probably more like a summer breeze
Re: Does light have an infinite lifetime?
#9Interesting. I had no idea that the universe would eventually be basically just photons. I wonder if that is why Stephen Baxter had his 'photino birds' as the final form of life in his Xeeleverse?
There is some debate whether this is knowable, some particles are not believed to decay into light at a rate faster than their spontaneous creation from light. (And humanity wont be around to check).
Re: Does light have an infinite lifetime?
#10Interesting. I had no idea that the universe would eventually be basically just photons. I wonder if that is why Stephen Baxter had his 'photino birds' as the final form of life in his Xeeleverse?
The photino birds want the universe to be populated with white dwarfs, because they can feed off their gravity wells without the risk of deadly supernovas and black holes, which can kill them.
After the xelee and humans leave, the universe becomes a cold place dominated by photino birds living in the cold pinpricks of white dwarfs. Eventually matter evaporates into photons, and the photino birds die.
However, it turns out photino birds can always just time travel to a time when the universe still had matter. So they're more or less indifferent to the eventual heat death .
See: https://xeelee.fandom.com/wiki/Photino_Birds
I hypothesize that there is may be only one photino bird. When it appears to die, it is just traveling to another time. When we see multiple photino birds, we're just looking at different segments of the same bird's world line. These are my own speculations, inspired by Wheeler's idea that the universe has only one electron, which travels back in time as a positron, and interacts with itself so many times that it creates the observable universe of matter: